Properties Of Soil Including Density And Porosity Environmental Sciences Essay

Properties Of Soil Including Density And Porosity Environmental Sciences EssayExperiments were undertaken to become the batch constriction, particle closeness, and stigma porosity of foursome crap samples. pop concentration, particle tightness, and defacement porosity are all interrelated terms. Density is the relationship between the mass (m) and volume (V) of a substance. . found on this relationship, an object or substance that has luxuriously mass in relation to its size (or volume) also has a high density (D). Soil mass density (Db) is a measure of the mass of soil per unit volume ( immobiles + pore space) and is usually reported on an oven-dry basis. The particles that make up a soil progress to a specific particle density (Dp), which is defined as the mass of solid particles in a unit volume. This can be verbalised as, . The particle density of a soil is not change by particle size or arrangement rather it depends on the type of solid particles bow in the so ils. Unlike the measurement of particle density, the bulk density measurement accounts for the spaces between the soil particles (pore space) as well as the soil solids. Soils with a high proportion of pore space name write down mass per unit volume, and on that pointfore buzz off low bulk density. A bulk density greater than 1.6 g cm-3 may indicate soil compaction, which means these soils have a low proportion of pore space and, therefore, low porosity. The bulk density indirectly provides a measure of the soil porosity which is the ratio of the volume of soil pores to the total soil volume. Clayey soils generally have an abundance of rattling small pores that give them a higher total porosity compared to sands, which are dominated by larger, but fewer pores.MATERIALS1. Core soil samples2. Balance (0.1 g precision)3. Flat-bladed knife4. Veneer calliper5. Disturbed soil samples6. 100 ml measuring cylinder7. De-aired wetMETHODThe bulk density of the soil was reckon after follo wing a series of steps. Firstly, excess soil from each of the disturbed soil sample was removed development a flat-bladed knife, ensuring that the bottom of the sample was flat and even with the edges of the ring. Excess material or roots penetrating from the sample was cut using a scissors. The dimensions of the core were then measured using a veneer calliper and the dimensions obtained were plugged into the formula Volume= * radius 2* height to calculate the volume of the core. This pass judgment was then used to obtain the bulk density of the soil (Db = ). Afterwards, approximately 50g of soil was weighed out in a weigh dish for each soil sample and the soil weight was recorded to the nearest 0.1 g. e 50 cm of water was then poured into a 100 ml graduated cylinder and the previously weighed soil was added into the water in small increments. Air bubbles were eliminated by stirring with a rod and the final volume of the soil water suspension was read and the value was recorded. This value was then used to calculate the particle density of each soil sample (Dp = ). Using the measured densities the percentage soil porosity was calculated via the formula, 100-( Db / Dp * 100). Data was recorded and presented in a tabular format.RESULTS dirt SAMPLEHEIGHT OF substance (cm)DIAMETER OF CORE (cm) glitz OF CORE taste-tester (cm3)15.5485.36125.223.8625.5894.534.8895.858131.844.7985.384109.2FIGURE 1 TABLE SHOWING THE HEIGHT, DIAMETER AND VOLUME OF THE CORE SAMPLER FOR EACH crack SAMPLE.SOIL SAMPLEWEIGHTVOLUME (cm3)1319.6g692276.6g693273.2g714343.6g70TABLE SHOWING THE WEIGHT AND VOLUME OF THE FOUR SOIL SAMPLES.SOIL SAMPLEWEIGHT OF FIELD MOIST SOIL SAMPLE (g) WITH COREWEIGHT OF DRY SOIL SAMPLE (g) WITH COREWEIGHT OF CORE (g)WEIGHT OF DRY SOIL SAMPLE (g) (WEIGHT OF DRY SOIL WITHOUT CORE WEIGHT)1356.7319.5188.51312277.4276.6105.1171.53390.1273.2145.8127.44245.6343.6104.5239.1FIGURE 1 TABLE SHOWING WEIGHT OF FIELD MOIST SOIL SAMPLE AND OVEN DRY SOIL SAMPLE.SOIL SAMPLE WEIGHT OF SOIL SAMPLE (g)initial VOLUME OF WATER (cm3)FINAL VOLUME OF WATER (cm3)VOLUME OF THE SOIL PARTCLES (cm3)150.00506919250.00506919350.00507121450.00507020FIGURE 4 TABLE SHOWING WEIGHT OF SOIL SAMPLE, sign VOLUME OF WATER, FINAL VOLUME OF WATER AND VOLUME OF SOIL PARTICLES.SOIL SAMPLEBULK DENSITY (g/cm-3)PARTICLE DENSITY (g/cm-3)SOIL POROSITY (%)11.96.972.522.499.0372.431.86.170.543.421271.5FIGURE 2 TABLE SHOWING THE BULK DENSITY, PARTICLE DENSITY AND SOIL POROSITY OF EACH SOIL SAMPLE.To calculate how many grams of soil are in a hectare plow layerDepth = 15cm =0.15mHectare = 10,000m2Volume of HPL = Area of Hectare * Depth of plow= 10,000 * 0.15= 1500m3Db = 1.4g/cm3=1kg = 1000g1400kg=1400 -1,000= 1,400,000gTherefore, there are 1,400,000g of soil in a hectare plow layer.DISCUSSIONSoil porosity and bulk density are interrelated terms. Soil bulk density (Db) is a measure of the mass of soil per unit volume while soil porosity is the ratio of the volume of soil pores to the total soil volume. multitude density (Db) is closely related to the soil porosity through the following relationship. The bulk density indirectly provides a measure of the soil porosity (amount of pore space). The value obtained from the measurement of soil bulk density can be used to calculate pore space. For soils with the same particle density, the lower the bulk density, the higher the percent pore space or total porosity. Soil porosity values range from 0 to 1. Soils with a high bulk density have low total porosity be thrust empty pores do not have any mass. When the bulk density is zero, porosity equals 1, meaning there are no particles. If the bulk density is equal to the particle density, then there are no pores and porosity is zero.Soil porosity can be affected by changes occurring in the soil. The porosity of the soil decreases in compacted subsoils and increases in well- aggregated, high organic matter surface soils. The values range from as low as 25% to more than 60% respec tively. Soil management can also alter soil porosity values such that, cultivated soils tend to have a lower total pore space as a result of a decrease in organic matter content and a consequent lowering of granulation, in comparison to uncultivated soils.Bulk density and porosity are also affected by changes in soil texture. Fine-textured soils including cadaver, clay loam and silt loams typically have lower bulk densities as compared to sandy soils, due to the presence of pores between and within the granules. As a result, these fine-textured soils containing a high proportion of pore spaces to solids tend to have low bulk densities. Sandy soils, on the other hand, though larger in particle size have larger yet fewer pore spaces, resulting in a higher bulk density. In terms of porosity, fine-textured soils are very porous. This is because of the large amount of mi discerpores in fine-textures soils which allow water to be held. These micropores prevent the water from being draine d away and therefore, result in high total porosity. In contrast, sandy soils have less total porosity due to the relative absence or lack of fine, within-ped pores. This allows water to be drained away easily through the macropores present in sandy soils. Additionally, bulk density and porosity are affected by changes in the size class of the soil particles. Bulk density is lower in sandy soils or well-sorted sand where the particles are generally of one size class whereas a mixture of different size particles (well-graded sand) will cause a high bulk density. In well-graded sand the smaller particles partially fill in the spaces between the larger particles causing a reduction in the pore spaces and a resultant increase in bulk density. Soil porosity, on the other hand, is decreased in well-graded sand as compared to well-sorted sand.Another agentive role impacting bulk density and porosity is compaction. Soil compaction refers to the disruption and reduction of the large pores w ithin the soil. It can be caused in a variety of slipway such as, the practice of poor agricultural practices, use of machinery on soil, etc. Compaction increases the mass in a given volume, which increases the measured bulk density. Bulk density increases because both the micropores and macropores in a soil are significantly reduced after compaction has taken place. Therefore, with the removal of these empty pores, the mass of soil increases in a given volume. With regards to porosity, compaction reduces the total pore spaces and hence, the total porosity.In conclusion, bulk density and porosity are two interrelated soil properties which are altered by various factors including soil texture, compaction and soil structure. Calculations into the bulk density and porosity were carried out. Some limitations presented were the fact that bulk density and porosity values would differ from place to place due to certain factors, for example, the level of compaction in an area. However, the se figures can be useful in determining the crop yield of a soil.